1. Field of the Invention
The present invention relates to a fabric for a substrate of printed circuit-boards used for computers, communication device, etc. and to printed circuit-boards therefrom.
2. Related Art
Generally, glass-epoxy laminates are used as printed circuit-boards; recently performances required for printed circuit-boards are so diversified due to developments in this field that the glass-epoxy laminates cannot satisfy the requirements in some cases. For instance, since a high speed signal propagation is put on with a gain of operating speed, a printed circuit-board of a low dielectric constant which is high reliable even used for a fast operating speed is demanded.
In compliance with this requirement, thermoplastic resins of a low dielectric constant such as polytetrafluoro-ethylene, polysulphone, polyethylene, polybutadiene are examined; and a fabric of polytetrafluoro-ethylene fiber, aromatic polyamide fiber, quartz fiber, etc. are examined. However, the above-mentioned printed circuit-boards prepared by the prior arts have problems as to processability, reliability as printed circuit-boards and the cost factor. Therefore, they cannot sufficiently meet the requirements yet.
Because a propagation delay of signal and a distortion of digital pulse shape are being noticed as problems with a gain of speed of information processing, printed circuit-boards prepared with materials of low dielectric constant are demanded. However, the development of such base materials for a substrate is delayed; a sufficient means in response to the above demand is not taken. Further, fabrics of D-glass fiber, quartz fiber and polyamide fiber are used on trial as materials for a substrate for a special use. But they are unsatisfactory in both cost and properties.